Storage/Stability

aqueous solutions of polysorbates undergo autoxidation during storage, with changes being catalyzed by light, increased temperature, and copper sulfate

autoclaving is not recommended without testing for changes in properties; TWEEN 20 may not be stable to autoclaving, particularly with metal cations in buffer solutions.

TWEEN 20 is heat sensitive and will darken when exposed to elevated temperatures

polysorbates have been reported to be incompatible with alkalis, heavy metal salts, phenols, and tannic acid

polysorbates may reduce the activity of many preservatives

no plastic incompatabilities have been observed

Comments

"I've recently been doing a series of experiments comparing the sensitivity of various ELISA protocols. One thing I have noticed, which is slightly annoying, is that on opening a new tin of skimmed milk (Marvel) and a new bottle of tween-20 (BDH) there are big reductions in the background. OK, so this may have been expected, but not to the extent that I have noticed. Both of the 'old' reagents had probably been opened less than 6 months ago." [4]